Equity (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jan. 21, 2016
Equity [Abstract]
Stock Repurchase Program, Authorized Amount	$ 400,000	$ 450,000	$ 300,000	$ 400,000
Treasury Stock, Shares, Acquired	1,356,892	4,145,440	2,530,608
Treasury Stock Value Acquired Cost Method Repurchase Agreement	$ 116,500	$ 375,300	$ 197,700
Treasury Stock, Value, Acquired, Cost Method	$ 122,916	$ 384,519	$ 201,525